It depends on a couple of things...I mean yes you can use snap edge if you want to for added insurance.
I've never used snap edge on regular dimensional 2x3' bluestone patios, our thicknesses are about 2-3".
But when it comes to irregular thermal cut bluestone, 1" mixed sizes we use a low profile snap edge to retain the edge.
it's a pain in the ass using poly sand with bluestone too. We've done with the thermal cut stuff, I think for the other bluestone we've used stone dust in the past.